Housing having a retention member for an optical fiber

ABSTRACT

The invention relates to an optical connector housing ( 100 ) for connecting an optical fiber to an optical element, such as a diode or a further optical fiber. The housing ( 100 ) comprises a substantially tubular receptacle ( 102 ) for one or more optical fibers and a retention member ( 104 ), which is received with interlocking fit in the housing ( 100 ) and is displaceable vertically to the optical fiber. In order to provide a housing ( 100 ) which fixes the optical fiber easily and inexpensively, yet securely, according to the invention the retention member ( 104 ) is manufactured from the same material and integrally with the housing ( 100 ). In the pre-assembly position, the retention member ( 104 ) is supported by webs ( 106 ) on the housing ( 100 ). During assembly, the retention member ( 104 ) is displaced in such a way that it engages the optical fiber and secures it against axial displacement.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a fiber optic connector and moreparticularly to a housing having a retention member for retaining anoptical fiber.

DESCRIPTION OF THE PRIOR ART

[0002] In complex data bus transmission systems, for example incommunications and information networks, plastic optical fibers areincreasingly being used for data transfer. Such systems ensure highrates of transfer, enable trouble-free signal transmission, areinsensitive to electromagnetic interference and reduce the cablingoutlay to cut down cost and weight. An application for such an opticalbus is in communications systems of a motor vehicle. For example, audiocomponents, CD changer, voice-controlled system, built-in car phone andfurther elements may connect to one another by an optical bus such as afiber-optic ring. Utilizing the fiber-optic ring, synchronous orasynchronous data transfer systems may be implemented at an adequatelyhigh baud rate.

[0003] Coupling of the optical fibers to the individual electroniccomponents or coupling of a plurality of optical fibers to one anotheris typically accomplished by special fiber optic connectors havinghousings in which an optical fiber is connected to another optical fiberor to an optical component.

[0004] Particularly in the field of motor vehicle electronics, becauseof extremely hostile ambient conditions, the connection of the opticalfibers has to meet stringent requirements with regard to resistance tovibration and corrosion but also with regard to thermal stability.Coupling of the optical fibers has to be achieved inexpensively andpreferably in an automated manner.

[0005] A conventional method of securing an optical fiber in a housingutilizes metal clips, as shown in FIG. 4. The housing 130 has areceptacle 102 for the optical fiber 122 and a receptacle 124 for ametal clip 120. The optical fiber 122 is positioned in the receptacle102 of the housing 130 and mechanically secured against axialdisplacement by insertion of the metal clip 120. This technique enablesthe mounting and latching of optical fibers having different lengths.The optical fiber 122 is secured by the metal clip 120 in the housing130 and hence ensures the connection to another optical fiber. Thissolution however has a drawback in that assembly always involves thepositioning of an additional metal part namely the clip 120. This addsto the cost of the assembly operation.

[0006] Another possible way of fastening optical fibers to a housing isby laser welding or other bonding techniques. However, the hardware andset up costs for these techniques is considerable. Additionally, thesetechniques result in a permanent connection between the optical fiberand the housing. Repair of the connection is therefore complicated.

SUMMARY OF THE INVENTION

[0007] An object of the present invention is to provide a fiber opticconnector housing for connecting an optical fiber to an optical element,which allows the optical fibers to be fastened as easily andinexpensively as possible.

[0008] This and other objects are achieved by providing an opticalconnector housing according to the invention for connecting an opticalfiber to an optical component. The housing has a retention member madefrom the same material as the housing. As a result, the retention memberand housing may be simultaneously formed, thereby reducing productioncosts.

[0009] According to one embodiment, the retention member is formedintegrally with the housing. Retaining webs are provided, which preventthe retention member in the pre-assembly state from falling out andbecoming lost and, may be broken during assembly by applying only slightforces to displace or engage the retention member.

[0010] A surface of the housing which receives the optical fiber may beprovided with teeth. This arrangement has the advantage that the opticalfiber is protected in a particularly effective manner from unintentionalaxial displacement. This arrangement also reduces the insertion forcesneeded to assemble the retention member.

[0011] According to a further embodiment, the retention member has areceptacle for a plunger of an assembly tool. The receptacle serves tofacilitate positioning of the assembly tool and assembly is thereforesimplified.

[0012] Recesses and guide projections may also be provided along thehousing to ensure that the retention member is displaced exactly normalto the optical fiber.

[0013] To prevent unintentional displacement of the retention member inthe assembled state, the guide projections may be bevelled in such a waythat they frictionally engage the retention member when inserted. Thisoffers the advantage of a reliable stop during assembly and allows theforces acting upon the optical fibers to be kept as low as possible.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The invention will now be described by way of example withreference to the accompanying figures of which:

[0015]FIG. 1 is a perspective view of a fiber optic connector housingfor connecting an optical fiber to an optical element according to afirst embodiment of the invention;

[0016]FIG. 2 is an inverted perspective view of the housing shown inFIG. 1;

[0017]FIG. 3 is a perspective view of a fiber optic connector housingfor connecting two optical fibers to optical elements according to asecond embodiment;

[0018]FIG. 4 is a perspective view of a conventional fiber opticconnector housing having a metal clip for fastening of the opticalfiber.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0019] Embodiments of the invention are described in detail below.Similar or corresponding elements of the illustrations according to theinvention are provided with the same reference numbers.

[0020] The drawings show only the elements of the housing, which may bemanufactured from injection moulding materials, such as plastics. Theoptical fiber, which has a circular cross section and is preferably alsomade of plastic, is not shown in the drawings and is not described indetail. Equally, for the sake of clarity, the optical elements, to whichthe optical fiber is to be coupled by the housing, are not shown in thedrawings. Such optical elements may be, for example, further opticalfibers or a diode or any passive or active optical component.

[0021] As shown in FIG. 1 in a first embodiment, the housing 100according to the invention comprises two substantially tubularreceptacles 102A, 102B each for receiving an optical fiber. A retentionmember 104, which is made of the same material as the rest of thehousing, is shown here in a pre-assembled state.

[0022] Frangible retaining webs 106, which are manufactured integrallywith the retention member and the housing, fix the retention member 104in a pre-assembled position such that it does not project into theinsertion openings 102 a and 102 b. In the pre-assembled position, theoptical fibers may be inserted into the openings 102A, 102B without anyinsertion force.

[0023] Once the optical fibers have been properly positioned by a guide105 and a stop 107 in the interior of the housing 100, a plunger of anassembly tool, which is positioned in the receiving opening 110, is usedto apply an adequate insertion force in the direction of the arrow 112such that the retaining webs 106 are broken and the retention member 104is pushed vertically into the insertion region 102A and 102B. The teeth108A, 108B then engage the optical fibers.

[0024]FIG. 2 shows an inverted perspective view of the housing 100 shownin FIG. 1. Here it is possible to see the tubular receptacles 102A, 102Bfor the optical fibers, which are open in the region of the teeth 108A,108B of the retention member 104, so that the optical fibers are firmlyclamped after the retention member 104 has been urged into the insertionregion 102A, 102B.

[0025] The retaining webs 106, which are manufactured with the retentionmember 104 and the housing 100 in moulding operation, have to bedimensioned in such a way that guarantees reliable retention of theretention member 104 in the pre-assembly state and, enables theretention member 104 to be movable in the insertion direction 112 byapplying as low a force as possible. Guide projections 115A, 115Bguarantee that the retention member 104, is displaced in the insertiondirection 112 normal to the optical fiber. A bottom surface of theassembly tool may be utilized as a stop to prevent the retention member104 from being pressed too far in the insertion direction 112.Alternatively, however, the side surfaces 116A and 116B of the guideprojections 115 may be bevelled in such a way that the retention member104 is clamped tightly as it is further displaced in the direction 112.

[0026]FIG. 3 shows a housing 100 for connecting two optical fibers to anoptical component, which comprises diodes, according to a secondembodiment. The receptacles 102A, 102B for the optical fibers extend inan outward direction as tubular insertion aids. Situated at the oppositeside of the housing 100 to the receptacles 102A, 102B is a holdingdevice 118 for receiving the optical component (not shown). In thisembodiment, the retention member 104 is initially supported byintegrally moulded frangible retaining webs 106 in its pre-assembledstate on the housing 100. Teeth 108A, 108B are similarly situated on thesurfaces which engage the optical fibers. A receiving opening 110 for anassembly tool enables exact positioning of a plunger, which presses theretention member 104 inwards in order to fix the two optical fibers intothe receiving openings 102A and 102B.

[0027] While the embodiments show a housing 100 for coupling fibers tooptical components, the housing according to the invention might also bepart of a “cable-to-cable” coupling for interconnecting a plurality ofoptical fiber ends.

What is claimed is:
 1. A housing for receiving an optical fiber having areceptacle for the optical fiber, the housing comprising: a retentionmember being made of the same material as the housing and initiallysupported in a pre-assembly position over the receptacle on the housing.2. The housing according to claim 1, wherein the retention member isformed integrally with the housing.
 3. The housing according to claim 1,wherein the retention member further comprises teeth disposed on asurface of the retention member which engages the optical fiber.
 4. Thehousing according to claim 1, wherein the retention member furthercomprises a receptacle for receiving a plunger of an assembly tool. 5.The housing according to claim 1, wherein the housing further comprisesguide projections, along which the retention member is displaceable. 6.The housing according to claim 5, wherein the guide projections arebevelled such that the retention member is fixed by clamping wheninserted.
 7. The housing according to claim 1, further comprising atubular insertion aid formed as an extension in to the receptacle. 8.The housing according to claim 1, wherein the housing comprises tworeceptacles, into which two optical fibers are respectively insertablesubstantially parallel to one another and the optical fibers are fixableby means of the same retention member.
 9. An optical connectorcomprising: a housing having at least one receptacle which is open to afirst side and open to a second side thereof; a fiber being receivedthrough the first side in to the receptacle; and, a retention memberbeing received from the second side in to the receptacle and being inengagement with the fiber to retain the fiber within the receptacle. 10.The optical connector of claim 9 wherein the retention member isintegrally formed with the housing in a pre-assembled position over thesecond side of the receptacle.
 11. The optical connector of claim 10wherein the retention member is joined to the housing by at least onefrangible web.
 12. The optical connector of claim 9 wherein theretention member further comprises teeth disposed on a side thereof inengagement with the optical fiber.
 13. The optical connector accordingto claim 9 wherein the retention member further comprises a secondreceptacle for receiving a plunger of an assembly tool.
 14. The opticalconnector according to claim 9 wherein the housing further comprisesguide projections along which the retention member is displaceable. 15.The optical connector according to claim 14 wherein the guideprojections are bevelled such that the retention member is frictionallyfixed when inserted into the receptacle.
 16. The optical connectoraccording to claim 9 further comprising a tubular insertion aid formedas an extension into the receptacle.
 17. The optical connector accordingto claim 9 wherein the housing comprises two receptacles into which twooptical fibers are insertable substantially parallel to one another andsecured in the receptacle by the same retention member inserted from thesecond side.